The invention relates in general to weapons and in particular to weapons that operate on a combination of gas and recoil.
Combination gas and recoil weapons are generally “automatic” or “semi-automatic.” These weapons operate or function using ammunition recoil impulse and gas pressure. Combination gas and recoil operated weapons use gas pressure bled from the barrel during firing to power the gas system and ammunition recoil impulse for recoil operation. However, they may not operate properly when firing blank cartridges, limited range training rounds, non-lethal cartridges, and other low impulse cartridges. The reduced cartridge impulse provided by lower mass projectile systems and/or reduced chamber pressure results in reduced operating energy in the weapon. Consequently, the weapon cyclic rate may be reduced to the point of being non-functional.
Also, when trying to extract such low impulse cartridges from the weapon after firing, the cartridge case may get stuck in the weapon chamber, or the bolt may not unlock to extract the cartridge. This is due to the slower barrel recoil of the low impulse cartridges as compared to conventional ammunition. The low impulse cartridges also produce a longer duration of gas pressure in the chamber than do conventional ammunitions. The low impulse cartridges have high value for training and non-lethal operations, but lack the ability to effectively operate (function) the weapon.